Positioned in the high-speed airflow, an optical window will suffer from a severe aerodynamic thermal environment due to aerodynamic heating. Under this circumstance, images obtained by uncooled infrared imaging devices are prone to be affected by thermal radiation noise, which may reduce a SNR between an optical detection system and a detected target, as well as image quality. To obtain a clear image, it is required to correct aero-optical thermal radiation noise, and correction accuracy determines high-level image processing in the optical detection system. Therefore, techniques for correcting the thermal radiation noise are of great importance in the optical detection system.
Conventionally, there are two methods for correcting the thermal radiation noise: the first one is a photoelectric based correction method that establishes a relationship between shock wave radiation, image degradation and an operating wavelength according to characteristics of imaging device, optimizes and analyzes a seeker's operating wavelength, and finally selects an appropriate operating wavelength; the second is an optical window based correction method that reduces heating degree of an optical dome and thus correcting the thermal radiation noise by designing a proper window structure and cooling scheme. However, problems with the above-mentioned methods are that, both methods employ a pre-prevention mechanism that suppresses the thermal radiation noise in an initial stage, but they cannot facilitate image restoration for optical images already having the thermal radiation noise.